Signs & Symptoms

The usual presenting symptoms in people with mental retardation are impairment in adaptive functioning, rather than low IQ. Adaptive functioning refers to how effectively individuals cope with common life demands and how well they meet the standards of personal independence expected of someone in their particular age group, sociocultural background and community setting. Adaptive functioning may be influenced by factors such as education, motivation, personality characteristics, social and vocational opportunities and the mental disorders and general medical conditions that can coexist with mental retardation. Problems in adaptation are more likely to improve with remedial efforts than is the cognitive IQ.

It is useful to evaluate deficits in adaptive functioning by using information from one or more reliable independent sources (e.g., teacher evaluation, and educational , developmental and medical histories). Several interview scales have been designed to measure adaptive functioning or behavior (e.g., Vineland Adaptive Behavior Scales and the American Association on Mental Retardation Adaptive Behavior Scale). As in the assessment of intellectual functioning, consideration should be given to the suitability of the instrument to the person's sociocultural background, education, associated handicaps, motivation and cooperation. In addition, some behaviors that would normally be considered maladaptive (e.g., dependency, passivity) may be evidence of good adaptation in the context of the particular life setting of a person with mental retardation.

As a group, people with mild mental retardation typically develop appropriate social and communication skills during the preschool years (ages 0-5 years), and have minimal impairment in sensorimotor areas. They often are not distinguishable from children without mental retardation until a later age. By their late teens, they can acquire academic skills up to approximately the sixth-grade level. During their adult years, they usually achieve social and vocational skills adequate for minimum self-support, but may need supervision, guidance and assistance, especially when under unusual social or economic stress. With appropriate supports, individuals with mild mental retardation can usually live successfully in the community, either independently or in supervised settings.

As a group, most people with moderate mental retardation acquire basic communication skills during the early childhood years. They profit from vocational training and, with moderate supervision, can attend to their personal care. They can also benefit from training in social and occupational skills but are unlikely to progress beyond the second-grade level in academics. They may learn to travel independently in familiar places. During adolescence their difficulties in recognizing social conventions may interfere with peer relationships. In their adult years, the majority are able to perform unskilled or semiskilled work under supervision in sheltered workshops or in the general work force. They adapt well to life in the community, usually in supervised settings.

As a group, people with severe mental retardation acquire little or no communicative speech during the early childhood years. During the school-age period, they may learn to talk and can be trained in basic self-care skills. Their ability to profit from instruction in pre-academic subjects is limited. They can become familiar with the alphabet and simple counting, and can master skills such as learning sight reading of some 'survival' words. In the adult years they may be able to perform simple tasks in closely supervised settings. Most adapt well to life in the community, in supervised group homes or with their families, unless they have an associated handicap that requires specialized nursing or other care.

As a group, people with profound mental retardation have an identified neurological condition that accounts for the mental retardation. During the early childhood years they have considerable impairment in sensorimotor functioning. Optimal development may occur in a highly structured environment with constant aid and supervision and an individualized relationship with a caregiver. Motor development and self-care and communication skills may improve if appropriate training is provided. Some can perform simple tasks in closely supervised and sheltered settings.